package ioutil

import (
	diff "0dev.org/diff"
	"bytes"
	"io"
	"testing"
)

func TestWriter(t *testing.T) {
	var (
		input  []byte = []byte{0, 1, 2, 3, 4, 5, 6, 7}
		output []byte

		reader *bytes.Reader = bytes.NewReader(input)
		buffer bytes.Buffer
	)

	reader.WriteTo(WriterFunc(buffer.Write))
	output = buffer.Bytes()

	// Diff the result against the initial input
	delta := diff.Diff(diff.D{len(input), len(output),
		func(i, j int) bool { return input[i] == output[j] }})
	if len(delta.Added) > 0 || len(delta.Removed) > 0 {
		t.Error("Differences detected ", delta)
	}
}

func TestReader(t *testing.T) {
	var (
		input  []byte = []byte{0, 1, 2, 3, 4, 5, 6, 7}
		output []byte

		reader *bytes.Reader = bytes.NewReader(input)
		buffer bytes.Buffer
	)

	buffer.ReadFrom(ReaderFunc(reader.Read))
	output = buffer.Bytes()

	// Diff the result against the initial input
	delta := diff.Diff(diff.D{len(input), len(output),
		func(i, j int) bool { return input[i] == output[j] }})
	if len(delta.Added) > 0 || len(delta.Removed) > 0 {
		t.Error("Differences detected ", delta)
	}
}

func TestBlockReader(t *testing.T) {
	var (
		input  []byte = []byte{0, 1, 2, 3, 4, 5, 6, 7}
		output []byte = make([]byte, 16)

		reader *bytes.Reader = bytes.NewReader(input)
		min    io.Reader     = SizedReader(reader, 4)
	)

	// Expecting a read count of 2
	count, err := min.Read(output[:2])
	if count != 2 {
		t.Error("Invalid read count from MinReader", count)
	}
	if err != nil {
		t.Error("Unexpected error from MinReader", err)
	}

	// Expecting a read count of 2 as it should have 2 bytes in its buffer
	count, err = min.Read(output[:3])
	if count != 2 {
		t.Error("Invalid read count from MinReader", count)
	}
	if err != nil {
		t.Error("Unexpected error from MinReader", err)
	}

	// Expecting a read count of 4 as the buffer should be empty
	count, err = min.Read(output[:4])
	if count != 4 {
		t.Error("Invalid read count from MinReader", count)
	}
	if err != nil {
		t.Error("Unexpected error from MinReader", err)
	}

	// Expecting a read count of 0 with an EOF as the buffer should be empty
	count, err = min.Read(output[:1])
	if count != 0 {
		t.Error("Invalid read count from MinReader", count)
	}
	if err != io.EOF {
		t.Error("Unexpected error from MinReader", err)
	}
}
